New evidence from open-sea experiments shows there’s a constant shuffling of genetic material going on among the ocean’s tiny plankton. It happens via ocean-dwelling viruses, scientists report this week in the journal Science.
Conducted by biological oceanographers Sallie Chisholm and her colleagues at the Massachusetts Institute of Technology, the research is uncovering a new facet of evolution and helping scientists see how microbes exploit changing conditions, such as altered light, temperature and nutrients.
"These results tell us that even the smallest organisms show genetic variation related to the environment in which they exist," said Philip Taylor, director of the National Science Foundation (NSF)’s biological oceanography program, which funded the research.
In addition to NSF, support for the research came from the Gordon and Betty Moore Foundation and from the U.S. Department of Energy.
"Our image of ocean microbes and their role in planetary maintenance is changing," Chisholm said. "We no longer think of the microbial community as being made up of species that have a fixed genetic make-up. Rather, it is a collection of genes, some of which are shared by all microbes and contain the information that drives their core metabolism, and others that are more mobile, which can be found in unique combinations in different microbes."
The distributors or carriers of new genes, the scientists suspect, are the massive numbers of viruses also known to exist in seawater. Some of them are adept at infecting ocean microbes like Prochlorococcus, the sea’s most abundant plankton species. The ocean viruses, which carry their own genes as well as transport others, provide a way of transferring genes from old cells into new ones.
"We’re beginning to get a picture of gene diversity and gene flow in Prochlorococcus," Chisholm said. "These photosynthesizing bacteria form an important part of the food chain in the oceans, supply some of the oxygen we breathe, and play a role in modulating climate. It’s important that we understand what regulates their populations. Genetic diversity seems to be an important factor."
In one report, Chisholm and scientist Maureen Coleman suggest that gene-swapping in ocean microbes resembles the flow of genes already known to occur among disease-causing bacteria. In an ocean habitat, the exchange offers marine microbes a diverse palette of potential gene combinations, each of which might be best suited for a particular environment. "This would allow the overall population to persist despite complex and unpredictable environmental changes," said Chisholm.
A second report, by Zackary Johnson and Erik Zinser, compares where Prochlorococcus microbes are found with the conditions under which they thrive. These geographic patterns relate to environmental variables such as temperature, predators, light and nutrients.
Chisholm is trying to learn how the microbes function as a system in which they have co-evolved with each other, and with the chemistry and physics of the oceans. The studies show that all Prochlorococcus strains are very closely related, yet they display an array of physiologies and genetic diversity, Chisholm said.
"Genetic diversity is at the heart of the extraordinary stability of Prochlorococcus in the oceans, which maintain steady population sizes over vast regions of the sea," she said.
Cheryl Dybas | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy